Current high performance cylindrical pressure vessels generally have domed ends, which engenders a number of design and fabrication complexities. For one, such pressure vessels are not scalable. That is, it is not possible to transition from a first volume/pressure condition to a second volume/pressure condition by simply applying a proportionality multiplier to the dimensions of the domed end used in the one condition to arrive at proper dimensions of the domed end under the other condition. Rather, complex design and fabrication factors come into play that must be addressed ab initio.
Further, when a domed pressure vessel comprises a composite overwrap, a minimum of a three axis and preferably a four-axis filament winding is required. The third axis is a radial (cross-feed) axis perpendicular to carriage travel and the fourth axis is a rotating fiber payout head mounted to the cross-feed axis and is used to stop the fiber band from twisting and thereby varying band width during winding. Three and four axis winders are complicated and expensive.
In addition, when liners for conventional domed pressure vessels are fabricated, they are usually spin formed or roto-molded. This limits the type of materials that can be used to make the vessel.
Finally, pressure vessels currently in use for SCBA (Self-Contained Breathing Apparatus—used by first responders, etc.) or SCUBA (Self-Contained Underwater Breathing Apparatus—used for diving) applications, although relatively small, still generally have at least one domed end and must conform to the same design and fabrication requirements as large domed vessels, which results in their being heavy, cumbersome and relatively expensive.
What is needed, particularly with regard to small volume pressure vessels such as those for SCBA and SCUBA, is a scalable design that can be easily fabricated in a broad range of volume/pressure configurations, that does not require a dome at either end, and that, by virtue of these and other features, is relatively light in weight, easy to fabricate and inexpensive. In addition, it would be desirably if the pressure vessels had a relatively small profile which would facilitate use in confined spaces. The present invention provides such a pressure vessel.